the Canadian Paediatric Society. In IMPACT, a nurse monitor and clinical investigator regularly review admission records at network hospitals. Any suspected adverse events are reported to the vaccinee’s local public health authorities and the Public Health Agency of Canada (Public Health Agency of Canada, 2006). IMPACT data have been used in studies of suspected adverse events after immunization, including studies of the risk of seizures or encephalopathy after implementation of acellular pertussis-containing vaccines (Scheifele et al., 2003).

International Collaborations

In addition to country-specific data systems, some international collaborations seek to improve assessments of vaccine safety. The Brighton Collaboration is a global research network comprising more than 300 vaccine safety experts from 124 countries, including the United States. The focus of their work is to enhance vaccine safety and it falls into five categories: capacity building, clinical assessments, communication, data linkages, and research standards. Included in their activities is an effort to standardize case definitions of adverse events after immunization (Brighton Collaboration, 2012).

In addition, the Brighton Collaboration operates the Vaccine Adverse Event Surveillance and Communication Network of data linkages in Europe, which is funded by the European Centre for Disease Prevention and Control (VAESCO, 2010). To date, this network of investigative centers has conducted a five-country distributed case-control study to evaluate the risk of Guillain-Barré syndrome after administration of the pandemic influenza (H1N1) vaccine and the incidence of idiopathic thrombocytopenic purpura after immunization with MMR in a combined sample from Denmark and the United Kingdom (Dieleman et al., 2011; Madsen et al., 2002).

AHRQ (Agency for Healthcare Research and Quality). 2009. Overview of HCUP. Rockville, MD: Agency for Healthcare Research and Quality. http://www.hcup-us.ahrq.gov/overview.jsp (accessed September 19, 2012).